is user pushback followed by voting with one's feet if the vendor still doesn't get the message. I plck a UI to maximize my efficiency, and I saw nothing in Unity that would help me do that on a desktop. I wouldn't mind trying Unity on a tablet or smartphone. If Shuttleworth wants happy Unity users, he needs to convince OEMs to put it on tablets and smartphones.
So I run Kubuntu on all 4 of my machines, including the netbook. If some way is found to make it impossible to run KDE on Ubuntu, I'll go back to Debian.
But because all the OSes are going to be extended to the mobile, all the vendors are making changes to the DE at the expense of some discomfort of the users.
Desktops are not smartphones,. The main differences are far more screen real estate (true even on a netbook with the screen the size of a tablet ...netbooks don't need virtual keyboards or touchscreen cursor control), a physical pointing device, and a physical keyboard. Optimising a desktop with a smartphone UI is a great reason to change distros or operating systems.
Certainly, a single unified UI is convenient for developers. But if the price of developer convenience is mass migration to the competition, it's not worth paying.